Why are the minimum Powder Charges the minimum?

[cold1]

A little Background first. I started reloading in the preinternet days. I also stopped in the pre internet days. I only had a few reloading manuals and no Ol' timer to help. I learned from the books. Being a beginner and understanding my limitations I did not experiment outside of what was listed in the books. Today I have returned to reloading and found out that there is alot of information and history on the internet. Especially here at Castboolits!

I see printed in the manuals that there are minimum listed charges for each cartridge. There is nothing in the manuals explaining why this is "the minimum". Before the internet i never questioned this, today though I can find examples of cartridge/powder combinations that are well below whats listed in any Manual. Usually they are referred to as Gallery loads, cat sneeze loads, and mouse fart loads. If these reduced loads are out there why arent they listed in manuals? What makes the published minimums the industry standard minimums? Do the boolits stick in the barrel? Does the gun blow up? What is it that makes the published loads the lowest you should go?

Also why are there so many different minimums for the same cartridge/powder in different guns. For example the minimum 44mag pistol loading and then a different minimum for rifle? The cartridge didnt change so why the difference?

Please educate me.

Thanks.

[Petrol & Powder]

Lots of reasons!
1.They don't know what type of gun the loads will be fired in. Big cylinder to barrel gaps will reduce velocity. Slow bullets may stick in a long barrel but make it out of a short one, tight bores and big bullets will stick a bullet with a light load, etc. They set a minimum load that was safe and would always work.
2.Cast lead bullets require less pressure to achieve the same velocity as jacketed bullets.
3. Some powders behave very strangely at low pressures.
4. Some bullets can't tolerate high pressures (hollow base wadcutters for example)
There are just a lot of variables and the editors of those loading manuals wanted to be safe. They set minimum and maximum loads on lots of factors with safety being the overriding concern. Some are more conservative than others.

[str8wal]

For example the minimum 44mag pistol loading and then a different minimum for rifle? The cartridge didnt change so why the difference?

Perhaps it is because a longer barrel results in more drag on the bullet and a load that is powerful enough to clear the muzzle of a pistol with effective performance may be slowed too much in a rifle and needs a bit more snuff getting started. Every manufacturer has their own criteria and a question like this would be better asked of them. I don't know that I've ever had two load manuals of different companies agree on min and max loads, or expected performance, for any chambering I've loaded.

[big bore 99]

From what I understand, if a case has a smaller charge in it and the powder is laying flat along the length of it, it will cause it to burn faster and develop a pressure spike sooner. I shoot single shots and make it a habit to shake or tap in down against the primer before shooting. Dacron or other fillers may do the same thing, but I don't use them. Too many horror stories of ringed chambers or cylinders.

[dtknowles]

P&P covered it pretty well but I think I have something to add.

Most manuals call them starting loads not minimum loads. I have some guides that don't list anything but max and say reduce the load 10 percent and work up, except for certain powders.

Some old books listed gallery and mid range loads.

Nobody has published the comprehensive guide to Ammo, Handloads, reloads and front stuffers. As you can tell from this forum the is a lot of ground to cover. Like you I was self taught and started with a Hornady manual and some of their bullets and later got a Lyman manual and a mould, the journey continues.

Tim

[Green Frog]

There have been several good answers to this question so far, and in certain instances one or more of them may come into play. Another reason for a "minimum" loading might be that some powders require a certain minimum pressure to burn cleanly. I have observed a few powders that will begin to leave noticeable amounts of unburned powder in the barrel if your charge weight gets too low. It's counterintuitive but true! :?

I like the term, "starting weight" better than minimum, but either way, it's usually not a great idea to get too far below the recommended range for any powder. It would appear that the old "less is more" saw does not apply here! ;)

Froggie

[waksupi]

With light loads of slow powder, firearms can blow up. Search for Secondary Explosive Effect (SEE).

[country gent]

ALot of good reasons already given above. Another in the rifle loads is if you check the Starting loads almost none will allow for a double charge to fit in the case or be very obvious when check with a quick glance. Most of the gallery loads in rifle cases with pistol powders a double charge isnt very obvious and some will actually hold 4-5 charges of the light charges. Most reloaders arent interested in the light loads or plinking charges but in duplicating factory loads or bettering them. Some are most concerned with accuracy, but few are interested in the one gun concept for everything you hunt from squirells to moose. I have a light cast load worked up for my 300 win mag I use this rifle for all game hunting and have a few of these loads in my pocket for targets of oppurtunity. Turkey, grouse, rabbits, and squirells have all been taken with this load with little meat damage. I have an older lyman manual ( spiral bound) from the 50s or 60s that gave a lighter load or to for pelt hunters to lower damage to hides. Used to be a popular way to load ammo.

[montana_charlie]

Also why are there so many different minimums for the same cartridge/powder in different guns. For example the minimum 44mag pistol loading and then a different minimum for rifle? The cartridge didnt change so why the difference?
Do both lines of data use the same type of powder?

[1bluehorse]

Best answer so far has been they're not "minimum" loads.........they're "starting" loads....also has been stated, if one load only is listed consider it a "maximum" load and reduce from there to start..JMO..

[opos]

I went through a little "exercise" with a particular Speer J word bullet that had been listed in old manuals for use with a common powder...125 grain SJHP jword with 5.6 grains of the powder...the book said "do not reduce" and only showed the one combination...there are many loads in many books that use a combination of that same powder with a 125grain SJHP...I found the listed Speer combination was a dandy for what I was shooting and I used it for a long time...then as if by magic the load disappeared from the manual...I contacted Speer and asked why...their answer was they didn't want to see part of the jacked stay in the barrel...that was all they had to say...don't know if it was the bullet construction had changed or if they had new test data but for some reason the particular powder and SJHP bullet was no longer considered safe...I use the bullet in a 357 Mag these days with an entirely different powder and it's a listed load and shoots great...I guess the manufacturers really do track things and make changes.

[montana_charlie]

I found the listed Speer combination was a dandy for what I was shooting and I used it for a long time...then as if by magic the load disappeared from the manual.
Dang!
I'm gonna dig out my reloading manuals to see if any of the data in them has disappeared.
As old as they are, there might be entire pages that are now blank ...!?

CM

[cold1]

Thanks for the replies. Some reasons I knew and some I didnt. One of the reasons I was asking about it was that I was looking at the most recent Lyman reloading manual under the 45-70 heading. I was looking for a load with 4227 (currently all I have is 4227) and a 300 JHP. I couldnt find one in the trapdoor or marlin section (I use a Marlin) but I did find one in the contender section. Pressures were low, velocity was good enough for me. Being self taught, I didnt want to use something that wasnt listed in the correct section. Off to the internet I went to see what others were doing. Sure enough I found lots of reference to a 4227 load in 45-70 being used in Marlins. So this lead to me question why starting loads are starting loads. The internet search also lead me to gallery loads which am going to try next, along with reduced loads for 223. I think the reduced 223 loads will take the place of my 22LR until the prices return to a sane level.

[Petrol & Powder]

If it's on the internet it must be true......:veryconfu

Just because some idiot put it in print doesn't mean it is remotely true!

ALWAYS QUESTION THE SOURCE OF ANY INFORMATIOM !!!!
That includes alleged science, religion, academic studies, politics [particularly politics !!!!], the press, historical dogmatic reasoning and anything based on potential profit.

Question everything ! That doesn't mean you should reject sound reasoning and good science; it just means you should be willing and able to think for yourself.

Within the realm of reloading, you can generally trust entities that have something at stake (like their company's future) and are generally in line with other companies similarly situated. (4 different published reloading manuals list starting loads that are within a few grains of each other - that's a clue !!!)

Life is tough, it's even tougher when you're stupid. [attributed to John Wayne who was really Marion Robert Morrison, always check your source when money is involved !!!]

The fact that you're interested in finding good data is a sign that you're interested in finding the truth.

CARRY ON

[fast ronnie]

There are some powders such as 4831 when loaded below minimums can detonate. It is thought that the flame can travel over the top of the powder and ignite the whole charge at once, but this theory (to my knowledge) is only a theory and not proven. Apparently it usually only happens with the slower powders, but I had it happen with T322 in a custom wildcat. I was fortunate it didn't hurt anything, but won't go that low again. (I raised the starting load by 2 full grains and am starting over on that combination.)

[Doc Highwall]

Another thing to think about is most reloading manuals are for jacketed bullets where most re-loaders try to get the highest velocity or high end target loads. For the most part the only reloading manual for cast bullets has been the Lyman, yes RCBS had one a long time ago and a few loads for cast bullets, and in the Accurate Powder manual as well. Most cast bullet loads also start with lower velocities using faster powders that are not used with jacketed bullets.

[charlie b]

Blue Dot is one of those you have to be careful with. Loaded in a .45 Colt, up to max loadings it went well, velocities about what the book said. I loaded some lighter cartridges. When it got below the minimums listed I had the 'explosive' effect. First round was as expected, about 800fps. Second round kicked like one of the heavy loads and vel was near 1500fps. I tipped the barrel up, lowered it gently to level and fired again, about 800fps again.

So when you go below minimums, especially when the load is near 50% capacity, you can run into trouble.

[Clark]

I have found in 45 Colt with reduced loads of H110 250 gr, the roll crimp vs no crimp makes a large difference in what is the practical minimum load.
Without a crimp the revolver can jam with a bullet in the forcing cone when none of the 21 gr of powder burns.

[dtknowles]

I have found in 45 Colt with reduced loads of H110 250 gr, the roll crimp vs no crimp makes a large difference in what is the practical minimum load.
Without a crimp the revolver can jam with a bullet in the forcing cone when none of the 21 gr of powder burns.

Heresy, reduced loads of H110. You trying to blow up that gun. Don't you know about SEE.

What if you get a hang fire with that bullet lodged in the throat. I am skeptical about the whole SEE thing but you will not see me using reduced loads of H110.

Tim

[Clark]

Heresy, reduced loads of H110. You trying to blow up that gun. Don't you know about SEE.

What if you get a hang fire with that bullet lodged in the throat. I am skeptical about the whole SEE thing but you will not see me using reduced loads of H110.

Tim

I read all that stuff... I am sleepy
http://www.gmdr.com/lever/pistolpowi.htm

[MtGun44]

"There are some powders such as 4831 when loaded below minimums can detonate"

This is nonsense. The closest that has ever been proven, and that is difficult, is a very slow
powder and a long throat, where the bullet starts moving at very low pressure, then hits the
end of the throat and stops, while the pressure is still building. This is reported to have the
bullet act like a bore obstruction because it gets suddenly stopped after moving.

This is WAY different than "detonation". I have talked to experts who are in the powder
industry and they say powders cannot "detonate", but that some powders will burn inconsistently
and incompletely at too low pressures, possibly sticking a boolit, which CAN cause serious
problems.

Most real blowups are WAY too much powder, either accidental double charge or mistaking
a pistol powder for a rifle powder. 40 gr of a pistol powder will pretty much destroy any
rifle, where 40 gr of rifle powder in the same situation is a good load.

Many powders work very well far below the starting charges. The only powder that I am aware
of that has a specific recommendation not to reduce below certain levels is H110/W296. I
recently discussed this with a major figure in the powder industry and got assurances that
this was NOT due to big pressure increases, but due to inconsistencies in burning at low
pressures that could lead to a stuck boolit, with the next shot causing severe problems.
It is not because it might produce unintended high pressures when reduced too
much, it cannot do this.


Bill

[big bore 99]

Lots of good info on this thread. I've heard many things about SEE and detonations. I'm into the 45-70 single shot thing and have bought some Unique and am going to load some up. From what I've heard and been reading is that is good around 10 gr. for a 340 and 405 gr boolits. Think I'm on the right track here? In the past I've used mostly XMP 5744 and H and IMR 4198.

[Clark]

.. recommendation not to reduce below certain levels is H110/W296. I
...
this was NOT due to big pressure increases, but due to inconsistencies in burning at low
pressures that could lead to a stuck boolit,...

Bill

I got the same reaction from Hodgdon ~ 10 years ago in email.
I can't give a direct quote.
I can't dredge up email from that many computers ago.

I can see me posting about H110 reduced loads on forums in 2001, so I don't know who, I don't know when.